My users DB table was corrupted.
I used the PGV backup and the "User Information Migration tool" import to restore it.
1. I copied only the authenticate.php to my index directory. This caused the data of the news, messages, favorites and blocks to be deleted.
I think that if the files are not in the index directory and there is data in the DB tables, then the data should remain in the tables.
2. I then copied from the backup also the ...dat files to the index directory and imported again the data.
My new messages are normally shown in PGV with the newest first.
The restored messages are shown with the oldest first.